java 如何将选中的项目移动到列表的顶部
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How to move the selected item to move to the top of the list
提问by user339108
List<String> strings; // contains "foo", "bar", "baz", "xyz"
and if given an input "baz"the function re-arrange(String input) should return the strings
如果给定一个输入"baz"，函数 re-arrange(String input) 应该返回字符串
"baz", "foo", "bar", "xyz"
and if given an input "bar"the function re-arrange(String input) should return the strings
如果给定一个输入"bar"，函数 re-arrange(String input) 应该返回字符串
"bar", "foo", "baz", "xyz"
回答by sstendal
First, remove the item and then add the item again at position 1.
首先，删除该项目，然后在位置 1 处再次添加该项目。
List<String> strings;
List<String> rearrange(String input) {
strings.remove(input);
strings.add(0,input);
return strings;
}
回答by Mike Samuel
public static <T> List<T> rearrange(List<T> items, T input) {
int index = items.indexOf(input);
List<T> copy;
if (index >= 0) {
copy = new ArrayList<T>(items.size());
copy.add(items.get(index));
copy.addAll(items.subList(0, index));
copy.addAll(items.subList(index + 1, items.size()));
} else {
return items;
}
return copy;
}
回答by Mines Valderama-Hababag Hernan
public static <T> void setTopItem(List<T> t, int position){
t.add(0, t.remove(position));
}
回答by Navigateur
To move the original item to the top of the original list:
要将原始项目移动到原始列表的顶部：
public static <T> void rearrange(List<T> items, T input){
int i = items.indexOf(input);
if(i>=0){
items.add(0, items.remove(i));
}
}
